Bis(hydroxy-isoindolinone)s: synthesis, stereochemistry, polymer chemistry, and supramolecular assembly

Pseudoacid chlorides of 2,5-bis(4-fluorobenzoyl) terephthalic acid and 4,6-bis(4-fluorobenzoyl) isophthalic acid condense with primary amines to afford diastereomeric bis(hydroxyindolinone)s in good isolated yields and with diamines to give high molecular weight poly(hydroxyindolinone)s. Bis-N-pyrenemethyl bis(hydroxyindolinone)s assemble, even in dipolar solvents such as DMSO, with macrocyclic diimide-sulfones to give [3]pseudorotaxanes stabilized by electronically complementary aromatic π−π-stacking and shape-complementary van der Waals interactions.

Topical delivery of a naproxen-dithranol co-drug: in vitro skin penetration, permeation, and staining

Purpose This work probed the topical delivery and skin-staining properties of a novel co-drug, naproxyl-dithranol (Nap-DTH), which comprises anti-inflammatory (naproxen) and anti-proliferative (dithranol) moieties. Method Freshly excised, full-thickness porcine ear skin was dosed with saturated solutions of the compounds. After 24 h, the skin was recovered and used to prepare comparative depth profiles by the tape-stripping technique and to examine the extent of skin staining. Results Depth profiles showed that Nap-DTH led to a 5-fold increase in drug retention in the skin compared to dithranol. The application of Nap-DTH also demonstrated improved stability, resulting in lower levels of dithranol degradation products in the skin. Furthermore, significantly less naproxen from hydrolysed Nap-DTH permeated into the receptor phase compared to naproxen when applied alone (0.08 ± 0.03 nmol cm-² and 180 ± 60 nmol cm-², respectively). Moreover, the reduced staining of the skin was very apparent for Nap-DTH compared to dithranol. Conclusions Topical delivery of Nap-DTH not only improves the delivery of naproxen and dithranol, but also reduces unwanted effects of the parent moieties, in particular the skin staining, which is a major issue concerning the use of dithranol.

Antifeedant activities of crude seed extracts of tropical African spices against Spodoptera littoralis (Lepidoptera: Noctuidae)

The antifeedant activities of Piper guineense Schum et Thonn (Piperaceae), Aframomum melegueta (Rosk) K. Schum (Zingiberaceae), Aframomum citratum (Pareira) K. Schum (Zingiberaceae) and Afrostyrax kamerunensis Perkins and Gilg (Huaceae) seed extracts were investigated in laboratory dual- and no-choice bioassays using third-instar Spodoptera littoralis (Boisduval) larvae. In the dual-choice test, the hexane and methanol extracts of A. melegueta showed potent dose-dependent antifeedant activity at concentrations of ≥300 ppm and the water extract at ≥500 ppm, as illustrated by significantly lower leaf consumptions. Aframomum citratum methanol and water extracts exhibited antifeedant activity at ≥300 and ≥1000 ppm, respectively, but the hexane and ethanol extracts did not affect feeding at any concentration. Piper guineense ethanol and water extracts showed dose-dependent antifeedant effects at ≥300 and ≥500 ppm, respectively, and the methanol extract was active only at 1000 ppm. None of the extracts of the highly aromatic A. kamerunensis exhibited antifeedant activity at any of the tested concentrations. In the no-choice bioassays, extracts with antifeedant activity in the dual-choice tests also showed dose-dependent feeding inhibition. The hexane and methanol extracts of A. melegueta were effective in the no-choice tests at ≥100 and ≥500 ppm, respectively, and the water extract at ≥300 ppm. Similarly, the A. citratum water and methanol extracts were active at ≥500 ppm and the P. guineense water and ethanol extracts at ≥100 ppm. GC/MS chromatography of A. melegueta hexane and methanol extracts revealed volatile constituents with known anti-insect activity. The hexane and methanol extracts of A. melegueta, the methanol extract of A. citratum and the water and ethanol extracts of P. guineense may have potential for use by subsistence farmers.